I’ve noticed a nice new trend in web / cloud apps recently. Apps where the homepage is an editable version of the service itself, explaining the service while also giving you a one-click option to save your own unique instance to share or come back to.
The example that inspired this post was this very useful Lean Business Model creator: http://www.netprofess.com/canvas.php but a similarly well-executed example is this great cloud-based notepad: http://notepad.cc/.
This is such a nice way of showing off your app and encouraging people to play with and explore it. You’re completely removing all barriers to entry and turning visitors into users without them even thinking about it.